matrix: add type cast function

Makefile.am

@@ -85,6 +85,7 @@ UTIL_FILES   =		\
     maths.ipp		\
     maths/matrix.cpp	\
     maths/matrix.hpp	\
+    maths/matrix.ipp	\
     maths/vector.cpp  	\
     maths/vector.hpp  	\
     matrix.cpp		\

matrix.hpp

@@ -57,6 +57,9 @@ namespace util {
 
         bool is_affine (void) const;
 
+        template <typename U>
+        matrix<U> cast (void) const;
+
         // Perspective matrices
         static matrix<T> ortho   (T left, T right, T bottom, T top, T near, T far);
         static matrix<T> ortho2D (T left, T right, T bottom, T top);
@@ -81,5 +84,6 @@ namespace util {
     std::ostream& operator<< (std::ostream&, const matrix<T>&);
 }
 
+#include "matrix.ipp"
 
 #endif

matrix.ipp

@@ -0,0 +1,39 @@
+/*
+ * This file is part of libgim.
+ *
+ * libgim is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * libgim is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with libgim.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2011-2014 Danny Robson <danny@nerdcruft.net>
+ */
+
+
+#ifdef __UTIL_MATRIX_IPP
+#error
+#endif
+
+#define __UTIL_MATRIX_IPP
+
+template <typename T>
+template <typename U>
+util::matrix<U>
+util::matrix<T>::cast (void) const
+{
+    util::matrix<U> out;
+
+    for (size_t i = 0; i < rows; ++i)
+        for (size_t j = 0; j < cols; ++j)
+            out.values[i][j] = values[i][j];
+
+    return out;
+}